The Fourth Dimension: The Evolution of 4D Printing

By now, you have likely been wowed by the incredible technology of 3D printing. Currently, 3D printing is one of the most popular areas for technology research, as the industrial applications are abundant. Not only that, 3D printers have saturated the market, and are becoming increasingly more affordable and available to the public; you may even know someone with a 3D printer in their home. With a 3D printer, one can turn a digital file into a three-dimensional object before their very eyes, which seems to offer endless possibilities.1 It may seem like 3D printing, also known as additive manufacturing, has only just been invented, but in actuality, it has been 30 years in the making.2 As 3D printing has turned a corner, so comes the new technology that everyone is talking about: 4D printing.

What is 4D Printing?

4D Printing uses 3D-printing technology and takes it to the next level. You could think of 4D printing as adding a fourth dimension to 3D printing: time. Essentially, 4D printing creates a three-dimensional object that changes according to its environment.3 4D printing uses geometric code so that the printed object can transform by itself.4 These “smart objects” can assemble themselves or change shape according to their environment. This exciting new technology has caught the attention of a variety of industries due to its many potential uses.

History

4D printing is a new technology that has only been in development since 2013.5 However, 3D printing — its predecessor that is essential to the technology, has been evolving over the last 30 years. It may seem as though 3D printing is newer than that because there have been so many recent innovations with the technology, but it all began in the 1980s with Charles Hull, co-founder of 3D Systems.6 In 1986, he patented stereolithography, a process that used digital data to create a three-dimensional model.7 In 1992, 3D systems created the first machine that performed this technique, called a stereolithographic apparatus (SLA) machine. Meanwhile, the two other main 3D printing technologies were being invented. In 1988, Carl Deckard of the University of Texas patented SLS technology, which 3D prints using a laser to fuse together powder grains.8 That same year, Scott Crump, co-founder of Stratasys, patented the Fused Deposition Modelling (FDM) method of 3D printing, the most commonly used today.9 In Europe, EOS GmbH was founded by Hans Langer, which created the first “Stereos” system that offered the first production applications for 3D printing.

In the 1990s, the world of 3D printing expanded, with new leaders emerging with new technologies. In 1992, Stratasys patented FDM, leading others to develop new ways to 3D print. Tools for 3D printing became more widely available, facilitated in part by the Sanders Prototype (now Solidscape) that was one of the first players to offer tools specifically designed for additive manufacturing.10 The ‘90s also saw incredible new applications for 3D printing in the medical field; the first lab-grown organ was engineered at the Wake Forest Institute for Regenerative Medicine, opening up the door for a 3D printed prosthetic leg, mini-kidney, and blood vessels.11

In 2004, the first self-replicating 3D printer was created. This enabled the mass production of these machines, and now people could have them in their homes. In 2005, the first color 3D printer was released by ZCorp.12 In 2009, the FDM patent was released to the public domain, which facilitated the invention of a slew of FDM 3D printers, the lowering of the price of 3D printers, and more visibility around this technology. Since then, the production of 3D printers has skyrocketed, and public awareness of 3D printing is higher than ever; in his 2013 presidential State of the Union address, Barack Obama mentioned 3D printing as a major issue for the future of the country.13 In the last ten years, 3D technology has seen giant leaps within the medical and commercial industries. In 2013, head of the Self-Assembly Lab of MIT Skylar Tibbits started research into 4D printing, which continues to develop today thanks to the teamwork of Self-Assembly Lab, Stratasys, and Autodesk.14 Today, with the new evolution of 4D technology, we have seen that the future is full of more incredible developments.

How it Works

A 4D printer is essentially a 3D printer that has been adapted to be able to print “smart” materials.15 3D printers use a layering process to create shapes, whether by SLA or any of the other methods. Regardless of which method is used, the basic premise of 3D printing is to successively build layers on top of one another to create a shape. In 4D printing, this same process is used, but is applied to create models that can change themselves. During the process, the smart material bonds with the plastic used to print the object and can absorb water. Once the object is printed, the water in the smart material expands, causing the shape to change. This enables the printed object to have several different dimensions; it could go from a 1D object to 3D, a 2D surface to a 3D object, or morph from one 3D shape to another.16 Each 4D model is specially designed to react and form a new shape when the water expands. While water is used in current prototypes, this material could potentially be made out of a variety of activation materials, such as temperature, vibration, pressure, or light. Once these new activation methods have been fully developed, the possibilities are endless.

Military Applications

The military has shown interest in 4D printing, granting a $855,000 grant to the 4D research efforts of a team of researchers from The University of Illinois, The University of Pittsburgh Swanson School of Engineering, and Harvard University’s School of Engineering and Applied Science, respectively.17 While the research is still in its infancy, there are a lot of potential military applications for this technology. For example, there is a vision of a military vehicle that adapts to the environment in order to protect it from damage and corrosion.18 Additionally, there is talk of uniforms that are able to transform based on environment to better camouflage soldiers or to protect against poisonous gases or shrapnel, as well as self-assembling weaponry.19 This investment in 4D technology reflects the U.S. military’s desire to have a firm technological advantage in the battlefield, and 4D printing may reveal itself to be a great boon in the future.

Commercial Applications

The concept of 4D technology already has several commercial industries excited, and it isn’t hard to understand why. One such industry is the sportswear industry.20 Research is currently being conducted on a “smart shoe,” which would be able to turn into a running shoe when you run that would turn waterproof when you meet a puddle or otherwise adapt to changes in the environment. While many experiments have been conducted into other commercial applications for 4D printing, one can imagine how every industry could ultimately benefit. For example, boxes printed on a 4D printer would be able to unfold and refold themselves.21 Businesses could ship their inventory in these boxes, the boxes would fold themselves, and they could ship them back to the warehouse, saving them millions of dollars on the cost of shipping materials. Just imagine buying a piece of furniture and having it assemble itself once it is out of the box!22 4D printing could revolutionize so many industries that we cannot even fathom everything it will bring. When thinking along these lines, the possibilities are endless.

Medical Applications

Perhaps most astounding developments are the potential medical applications for 4D printing. Currently, the ARC Centre of Excellence for Electromaterials Science (ACES) at Wollongong University is researching 4D printing applications for medicine.23 As we know, 3D printing has already revolutionized the medical field by making prosthetics and implants as well as fabricating tissues and organs.24 4D printing has the potential to be even more radical. One area of research currently being explored is the idea of 4D-printed medical implants.25 These implants could change shape according to changes in the body. For example, a 4D-printed cardiac tube could change shape in response to a sudden change in blood pressure. Additionally, this technology could be used to make drug capsules that release medication in response to illness; for example, if it were to respond with body temperature, the drugs would be released immediately when a fever begins.26

Future Expectations

In the future, 4D printing will have completely changed our world. Houses will be delivered to you in boxes and will assemble themselves. Bridges will never collapse because they will have the ability to repair any damage they experience.27 Your pipes will never freeze because they will be able to expand, contract, and adjust temperature according to the weather. Our clothes will adapt according to temperature and climate. We will live longer because our wearable medical technology will let us know the moment there are any health concerns on the horizon. We will be able to build structures on other planets because we will be able to send materials to deep space without the need for human beings or robots.28 Energy will be completely revolutionized as 4D printers will create solar panels that respond to temperature, expanding and contracting according to their settings.29 Once more research has been conducted, 4D printing promises to change life as we know it.

Further Reading

Interested in learning more about 3D and 4D printing? View the links below.